Method of forming a non-circular stent

ABSTRACT

A method for manufacturing a stent, includes the steps of winding stent wire around the outer surface of a longitudinal axis of a mandrel into a desired final shape that is polygonal in an elevation orthogonal to the longitudinal axis, and forming a stent by setting the wound stent wire in the desired polygonal final shape. The outside diameter of the stent formed will be in co-columnar apposition with a blood vessel in which it is implanted. The mandrel employed in the methods can have a multiple-sided outer surface and a longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 10/784,462, filed Feb. 23, 2004, which applicationclaims the benefit under 35 U.S.C. §119(e) of U.S. ProvisionalApplications Nos. 60/499,652, filed Sep. 3, 2003, and 60/500,155, filedSep. 4, 2003, the complete disclosures of which are each herebyincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention lies in the field of endoluminal blood vessel repairs. Theinvention specifically relates to a method for making a non-circularstent, which can be used to endoluminally repair aneurysm and/ordissections of the thoracic transverse aortic arch, thoracic posterioraortic arch, and the descending thoracic portion of the aorta.

2. Description of the Related Art

A stent graft is an implantable device made of a tube-shaped surgicalgraft covering and an expanding or self-expanding frame. The stent graftis placed inside a blood vessel to bridge, for example, an aneurismal,dissected, or other diseased segment of the blood vessel, and, thereby,exclude the hemodynamic pressures of blood flow from the diseasedsegment of the blood vessel.

In selected patients, a stent graft advantageously eliminates the needto perform open thoracic or abdominal surgical procedures to treatdiseases of the aorta and eliminates the need for total aorticreconstruction. Thus, the patient has less trauma and experiences adecrease in hospitalization and recovery times. The time needed toinsert a stent graft is substantially less than the typical anesthesiatime required for open aortic bypass surgical repair, for example.

Use of surgical and/or endovascular grafts have widespread usethroughout the world in vascular surgery. There are many different kindsof vascular graft configurations. Some have supporting framework overtheir entirety, some have only two stents as a supporting framework, andothers simply have the tube-shaped graft material with no additionalsupporting framework, an example that is not relevant to the presentinvention.

One of the most commonly known supporting stent graft frameworks is thatdisclosed in U.S. Pat. Nos. 5,282,824 and 5,507,771 to Gianturco(hereinafter collectively referred to as “Gianturco”). Gianturcodescribes a zig-zag-shaped, self-expanding stent commonly referred to asa z-stent. The stents are, preferably, made of nitinol, but also havebeen made from stainless steel and other biocompatible materials.

There are various features characterizing a stent graft. The firstsignificant feature is the tube of graft material. This tube is commonlyreferred to as the graft and forms the tubular shape that will,ultimately, take the place the diseased portion of the blood vessel. Thegraft is, preferably, made of a woven sheet (tube) of polyester or PTFE.The circumference of the graft tube is, typically, at least as large asthe diameter and/or circumference of the vessel into which the graftwill be inserted so that there is no possibility of blood flowing aroundthe graft (also referred to as endoleak) to either displace the graft orto reapply hemodynamic pressure against the diseased portion of theblood vessel. Accordingly, to so hold the graft, self-expandingframeworks are attached typically to the graft material, whether on theinterior or exterior thereof. Because blood flow within the lumen of thegraft could be impaired if the framework was disposed on the interiorwall of the graft, the framework is connected typically to the exteriorwall of the graft. The ridges formed by such an exterior framework helpto provide a better fit in the vessel by providing a sufficiently unevenouter surface that naturally grips the vessel where it contacts thevessel wall and also provides areas around which the vessel wall canendothelialize to further secure the stent graft in place.

One of the significant dangers in endovascular graft technology is thepossibility of the graft migrating from the desired position in which itis installed. Therefore, various devices have been created to assist inanchoring the graft to the vessel wall.

One type of prior art prosthetic device is a stent graft made of aself-expanding metallic framework. For delivery, the stent graft is,first, radially compressed and loaded into an introducer system thatwill deliver the device to the target area. When the introducer systemholding the stent graft positioned in an appropriate location in thevessel and allowed to open, the radial force imparted by theself-expanding framework is helpful, but, sometimes, not entirelysufficient, in endoluminally securing the stent graft within the vessel.

U.S. Pat. No. 5,824,041 to Lenker et al. (hereinafter “Lenker”)discloses an example of a stent graft delivery system. Lenker disclosesvarious embodiments in which a sheath is retractable proximally over aprosthesis to be released. With regard to FIGS. 7 and 8, Lenker namescomponents 72 and 76, respectively, as “sheath” and“prosthesis-containment sheath.” However, the latter is merely thecatheter in which the prosthesis 74 and the sheath 72 are held. Withregard to FIGS. 9 and 10, the sheath 82 has inner and outer layers 91,92 fluid-tightly connected to one another to form a ballooning structurearound the prosthesis P. This ballooning structure inflates when liquidis inflated with a non-compressible fluid medium and flares radiallyoutward when inflated. With regard to FIGS. 13 to 15, Lenker disclosesthe “sheath” 120, which is merely the delivery catheter, and aneversible membrane 126 that “folds back over itself (everts) as thesheath 120 is retracted so that there are always two layers of themembrane between the distal end of the sheath [120] and the prosthesisP.” Lenker at col. 9, lines 63 to 66. The eversion (peeling back) iscaused by direct connection of the distal end 130 to the sheath 120. TheLenker delivery system shown in FIGS. 19A to 19D holds the prosthesis Pat both ends 256, 258 while an outer catheter 254 is retracted over theprosthesis P and the inner sheath 260. The inner sheath 260 remainsinside the outer catheter 254 before, during, and after retraction.Another structure for holding the prosthesis P at both ends isillustrated in FIGS. 23A and 23B. Therein, the proximal holder havingresilient axial members 342 is connected to a proximal ring structure346. FIGS. 24A to 24C also show an embodiment for holding the prosthesisat both ends inside thin-walled tube 362.

To augment radial forces of stents, some prior art devices have addedproximal and/or distal stents that are not entirely covered by the graftmaterial. By not covering with graft material a portion of theproximal/distal ends of the stent, these stents have the ability toexpand further radially than those stents that are entirely covered bythe graft material. By expanding further, the proximal/distal stent endsbetter secure to the interior wall of the vessel and, in doing so, pressthe extreme cross-sectional surface of the graft ends into the vesselwall to create a fixated blood-tight seal.

One example of such a prior art exposed stent can be found in UnitedStates Patent Publication US 2002/0198587 to Greenberg et al. Themodular stent graft assembly therein has a three-part stent graft: atwo-part graft having an aortic section 12 and an iliac section 14 (withfour sizes for each) and a contralateral iliac occluder 80. FIGS. 1, 2,and 4 to 6 show the attachment stent 32. As illustrated in FIGS. 1, 2,and 4, the attachment stent 32, while rounded, is relatively sharp and,therefore, increases the probability of puncturing the vessel.

A second example of a prior art exposed stent can be found in U.S.Patent Publication 2003/0074049 to Hoganson et al. (hereinafter“Hoganson”), which discloses a covered stent 10 in which the elongatedportions or sections 24 of the ends 20a and 20b extend beyond themarginal edges of the cover 22. See Hoganson at FIGS. 1, 3, 9, 11a, 11b,12a, 12b, and 13. However, these extending exposed edges are triangular,with sharp apices pointing both upstream and downstream with regard to agraft placement location. Such a configuration of the exposed stent 20a,20b increases the possibility of puncturing the vessel. In variousembodiments shown in FIGS. 6a, 6b, 6c, 10, 14a, Hoganson teachescompletely covering the extended stent and, therefore, the absence of astent extending from the cover 22. It is noted that the Hoganson stentis implanted by inflation of a balloon catheter.

Another example of a prior art exposed stent can be found in U.S. Pat.No. 6,565,596 to White et al. (hereinafter “White I”), which uses aproximally extending stent to prevent twisting or kinking and tomaintain graft against longitudinal movement. The extending stent isexpanded by a balloon and has a sinusoidal amplitude greater than thenext adjacent one or two sinusoidal wires. White I indicates that it isdesirable to space wires adjacent upstream end of graft as closetogether as is possible. The stent wires of White I are actually woveninto graft body by piercing the graft body at various locations. SeeWhite I at FIGS. 6 and 7. Thus, the rips in the graft body can lead tothe possibility of the exposed stent moving with respect to the graftand of the graft body ripping further. Between the portions of theextending stent 17, the graft body has apertures.

The stent configuration of U.S. Pat. No. 5,716,393 to Lindenberg et al.is similar to White I in that the outermost portion of the one-piecestent—made from a sheet that is cut/punched and then rolled intocylinder—has a front end with a greater amplitude than the remainingbody of the stent

A further example of a prior art exposed stent can be found in U.S. Pat.No. 6,524,335 to Hartley et al. (hereinafter “Hartley”). FIGS. 1 and 2of Hartley particularly disclose a proximal first stent 1 extendingproximally from graft proximal end 4 with both the proximal and distalapices narrowing to pointed ends.

Yet another example of a prior art exposed stent can be found in U.S.Pat. No. 6,355,056 to Pinheiro (hereinafter “Pinheiro I”). Like theHartley exposed stent, Pinheiro discloses exposed stents havingtriangular, sharp proximal apices.

Still a further example of a prior art exposed stent can be found inU.S. Pat. No. 6,099,558 to White et al. (hereinafter “White II”). TheWhite II exposed stent is similar to the exposed stent of White I andalso uses a balloon to expand the stent.

An added example of a prior art exposed stent can be found in U.S. Pat.No. 5,871,536 to Lazarus, which discloses two support members 68longitudinally extending from proximal end to a rounded point. Suchpoints, however, create a very significant possibility of piercing thevessel.

An additional example of a prior art exposed stent can be found in U.S.Pat. No. 5,851,228 to Pinheiro (hereinafter “Pinheiro II”). The PinheiroII exposed stents are similar to the exposed stents of Pinheiro I and,as such, have triangular, sharp, proximal apices.

Still another example of a prior art exposed stent can be found inLenker (U.S. Pat. No. 5,824,041), which shows a squared-off end of theproximal and distal exposed band members 14. A portion of the exposedmembers 14 that is attached to the graft material 18, 20 islongitudinally larger than a portion of the exposed members 14 that isexposed and extends away from the graft material 18, 20. Lenker et al.does not describe the members 14 in any detail.

Yet a further example of a prior art exposed stent can be found in U.S.Pat. No. 5,824,036 to Lauterjung, which, of all of the prior artembodiments described herein, shows the most pointed of exposed stents.Specifically, the proximal ends of the exposed stent are apices pointedlike a minaret. The minaret points are so shaped intentionally to allowforks 300 (see Lauterjung at FIG. 5) external to the stent 154 to pullthe stent 154 from the sheath 302, as opposed to being pushed.

A final example of a prior art exposed stent can be found in U.S. Pat.No. 5,755,778 to Kleshinski. The Kleshinski exposed stents each have twodifferent shaped portions, a triangular base portion and a looped endportion. The totality of each exposed cycle resembles a castellation.Even though the end-most portion of the stent is curved, because it isrelatively narrow, it still creates the possibility of piercing thevessel wall.

All of these prior art stents suffer from the disadvantageouscharacteristic that the relatively sharp proximal apices of the exposedstents have a shape that is likely to puncture the vessel wall.

Devices other than exposed stents have been used to inhibit graftmigration. A second of such devices is the placement of a relativelystiff longitudinal support member longitudinally extending along theentirety of the graft.

The typical stent graft has a tubular body and a circumferentialframework. This framework is not usually continuous. Rather, ittypically takes the form of a series of rings along the tubular graft.Some stent grafts have only one or two of such rings at the proximaland/or distal ends and some have many stents tandemly placed along theentirety of the graft material. Thus, the overall stent graft has an“accordion” shape. During the systolic phase of each cardiac cycle, thehemodynamic pressure within the vessel is substantially parallel withthe longitudinal plane of the stent graft. Therefore, a device havingunsecured stents, could behave like an accordion or concertina with eachsystolic pulsation, and may have a tendency to migrate downstream. (Adownstream migration, to achieve forward motion, has a repetitivelongitudinal compression and extension of its cylindrical body.) Suchmovement is entirely undesirable. Connecting the stents with supportalong the longitudinal extent of the device thereof can prevent suchmovement. To provide such support, a second anti-migration device can beembodied as a relatively stiff longitudinal bar connected to theframework.

A clear example of a longitudinal support bar can be found in Pinheiro I(U.S. Pat. No. 6,355,056) and Pinheiro II (U.S. Pat. No. 5,851,228).Each of these references discloses a plurality of longitudinallyextending struts 40 extending between and directly interconnecting theproximal and distal exposed stents 20a, 20b. These struts 40 aredesigned to extend generally parallel with the inner lumen 15 of thegraft 10, in other words, they are straight.

Another example of a longitudinal support bar can be found in U.S. Pat.No. 6,464,719 to Jayaraman. The Jayaraman stent is formed from a grafttube 21 and a supporting sheet 1 made of nitinol. This sheet is bestshown in FIG. 3. The end pieces 11, 13 of the sheet are directlyconnected to one another by wavy longitudinal connecting pieces 15formed by cutting the sheet 1. To form the stent graft, the sheet 1 iscoiled with or around the cylindrical tube 21. See FIGS. 1 and 4.Alternatively, a plurality of connecting pieces 53 with holes at eachend thereof can be attached to a cylindrical fabric tube 51 by stitchingor sutures 57, as shown in FIG. 8. Jayaraman requires more than one ofthese serpentine shaped connecting pieces 53 to provide longitudinalsupport.

United States Patent Publication 2002/0016627 and U.S. Pat. No.6,312,458 to Golds each disclose a variation of a coiled securing member20.

A different kind of supporting member is disclosed in FIG. 8 of U.S.Pat. No. 6,053,943 to Edwin et al.

Like Jayaraman, U.S. Pat. No. 5,871,536 to Lazarus discloses a pluralityof straight, longitudinal support structures 38 attached to thecircumferential support structures 36, see FIGS. 1, 6, 7, 8, 10, 11, 12,14. FIG. 8 of Lazarus illustrates the longitudinal support structures 38attached to a distal structure 36 and extending almost all of the way tothe proximal structure 36. The longitudinal structures 38, 84, 94 can bedirectly connected to the body 22, 80 and can be telescopic 38, 64.

United States Patent Publication 2003/0088305 to Van Schie et al.(hereinafter “Van Schie”) does not disclose a support bar. Rather, itdiscloses a curved stent graft using an elastic material 8 connected tostents at a proximal end 2 and at a distal end 3 (see FIGS. 1, 2)thereof to create a curved stent graft. Because Van Schie needs tocreate a flexible curved graft, the elastic material 8 is made ofsilicone rubber or another similar material. Thus, the material 8 cannotprovide support in the longitudinal extent of the stent graft.Accordingly, an alternative to the elastic support material 8 is asuture material 25 shown in FIGS. 3 to 6.

SUMMARY OF THE INVENTION

The invention provides a method of forming a non-circular stent thatovercomes the hereinafore-mentioned disadvantages of theheretofore-known devices and methods of this general type and thatprovides a vessel repair device that implants/conforms more efficientlywithin the natural or diseased course of the aorta by aligning with thenatural curve of the aorta, decreases the likelihood of vessel puncture,increases the blood-tight vascular connection, retains the intraluminalwall of the vessel position, is more resistant to migration, anddelivers the stent graft into a curved vessel while minimizingintraluminal forces imparted during delivery and while minimizing theforces needed for a user to deliver the stent graft into a curvedvessel.

With the foregoing and other objects in view, there is provided, inaccordance with the invention, method for manufacturing a stent,including the steps of providing a mandrel with an outer surface havinga polygonal cross-sectional shape and a longitudinal axis, winding stentwire around the outer surface of the mandrel about the longitudinal axisinto a desired final shape, the desired final shape being polygonal inan elevation orthogonal to the longitudinal axis, and forming a stent bysetting the wound stent wire in the desired polygonal final shape.

With the objects of the invention in view, there is also provided amethod for manufacturing a stent, including the steps of providing amandrel with a multiple-sided outer surface and a longitudinal axis,winding a stent wire around the outer surface of the mandrel into adesired final shape substantially corresponding to a shape of the outersurface, and forming a stent by setting the wound stent wire into thedesired final shape.

In accordance with another mode of the invention, the mandrel isprovided with flat sections and rounded edge portions between the flatsections.

With the objects of the invention in view, the stent forming step iscarried out by setting the stent wire to have rounded edgescorresponding to the rounded edge portions of the mandrel and with flatsides corresponding to the flat sections of the mandrel.

With the objects of the invention in view, pins are placed on the outersurface of the mandrel longitudinally offset from one another andcorresponding to desired Z-stent apex locations and Z-stent apices areformed by winding the stent wire around the pins. In accordance with afurther mode of the invention, the pin placing step is carried out byplacing the pins on the mandrel to protrude perpendicularly from theoutside surface of the mandrel.

In accordance with an added mode of the invention, pins are placed on atleast some of the rounded edge portions of the mandrel longitudinallyoffset from one another and corresponding to desired Z-stent apexlocations and Z-stent apices are formed by winding the stent wire aroundthe pins.

In accordance with an additional mode of the invention, the pins areplaced at each of the rounded edge portions of the mandrel and thesetting step is carried out to form the stent with substantially linearstruts lying flat against the flat sections of the mandrel.

In accordance with yet another mode of the invention, the mandrel isprovided in a dodecahedron shape and the setting step is carried out onthe mandrel to form a Z-stent having six proximal and six distal apices.

In accordance with yet a further mode of the invention, two ends of thestent wire are fastened to one another to complete the stent.

In accordance with yet an added mode of the invention, the stent wire isinitially provided as a cold-drawn shape-memory wire and the settingstep is carried out by heat-treatment. In one embodiment, theheat-treatment step is carried out by exposing the shape-memory wire toa heat-setting temperature for a period of time with subsequentquenching as required to shape set the shape-memory wire to thethen-existing shape of the wire on the mandrel and obtain superelasticmechanical characteristics of the shape-memory wire.

In accordance with yet an additional mode of the invention, the settingstep by exposing the wire to a process that shapes the wire to thethen-existing shape of the wire on the mandrel selected from at leastone of the group consisting of a mechanical process, a thermal process,and a chemical process.

In accordance with still a further mode of the invention, the outersurface of the mandrel is provided with a polygonal cross-sectionalshape.

In accordance with still an added mode of the invention, the desiredfinal shape is polygonal in an elevation orthogonal to the longitudinalaxis.

In accordance with a concomitant mode of the invention, the mandrel isprovided with flat sections and rounded edge portions between the flatsections; and the stent forming step is carried out by setting the stentwire to have rounded edges corresponding to the rounded edge portions ofthe mandrel and with flat sides corresponding to the flat sections ofthe mandrel.

Other features that are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin a method of forming a non-circular stent, it is, nevertheless, notintended to be limited to the details shown because variousmodifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof, will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention, which are believed to be novel,are set forth with particularity in the appended claims. The invention,together with further objects and advantages thereof, may best beunderstood by reference to the following description, taken inconjunction with the accompanying drawings, in the several figures ofwhich like reference numerals identify like elements, and in which:

FIG. 1 is a side elevational view of a stent graft according to theinvention;

FIG. 2 is a side elevational view of a stent of the stent graft of FIG.1;

FIG. 3 is a cross-sectional view of the stent of FIG. 2 with differentembodiments of protrusions;

FIG. 4 is a perspective view of a prior art round mandrel for formingprior art stents;

FIG. 5 is a fragmentary, side elevational view of a prior art stent in aportion of a vessel;

FIG. 6 is a perspective view of a dodecahedral-shaped mandrel forforming stents in FIGS. 1 to 3;

FIG. 7 is a fragmentary, side elevational view of the stent of FIGS. 1to 3 in a portion of a vessel;

FIG. 8 is a fragmentary, enlarged side elevational view of the proximalend of the stent graft of FIG. 1 illustrating movement of a gimbaledend;

FIG. 9 is a side elevational view of a two-part stent graft according tothe invention;

FIG. 10 is a fragmentary, side elevational view of a delivery systemaccording to the invention with a locking ring in a neutral position;

FIG. 11 is a fragmentary, side elevational view of the delivery systemof FIG. 10 with the locking ring in an advancement position and, asindicated by dashed lines, a distal handle and sheath assembly in anadvanced position;

FIG. 12 is a fragmentary, enlarged view of a sheath assembly of thedelivery system of FIG. 10;

FIG. 13 is a fragmentary, enlarged view of an apex capture device of thedelivery system of FIG. 10 in a captured position;

FIG. 14 is a fragmentary, enlarged view of the apex capture device ofFIG. 13 in a released position;

FIG. 15 is a fragmentary, enlarged view of an apex release assembly ofthe delivery system of FIG. 10 in the captured position;

FIG. 16 is a fragmentary, enlarged view of the apex release assembly ofFIG. 15 in the captured position with an intermediate part removed;

FIG. 17 is a fragmentary, enlarged view of the apex release assembly ofFIG. 16 in the released position;

FIG. 18 is a fragmentary, side elevational view of the delivery systemof FIG. 11 showing how a user deploys the prosthesis;

FIG. 19 is a fragmentary cross-sectional view of human arteriesincluding the aorta with the assembly of the present invention in afirst step of a method for inserting the prosthesis according to theinvention;

FIG. 20 is a fragmentary cross-sectional view of the arteries of FIG. 19with the assembly in a subsequent step of the method for inserting theprosthesis;

FIG. 21 is a fragmentary cross-sectional view of the arteries of FIG. 20with the assembly in a subsequent step of the method for inserting theprosthesis;

FIG. 22 is a fragmentary cross-sectional view of the arteries of FIG. 21with the assembly in a subsequent step of the method for inserting theprosthesis;

FIG. 23 is a fragmentary cross-sectional view of the arteries of FIG. 22with the assembly in a subsequent step of the method for inserting theprosthesis;

FIG. 24 is a fragmentary cross-sectional view of the arteries of FIG. 23with the assembly in a subsequent step of the method for inserting theprosthesis;

FIG. 25 is a fragmentary, diagrammatic, perspective view of the coaxialrelationship of delivery system lumen according to the invention;

FIG. 26 is a fragmentary, cross-sectional view of the apex releaseassembly according to the invention;

FIG. 27 is a fragmentary, side elevational view of the stent graft ofFIG. 1 with various orientations of radiopaque markers according to theinvention;

FIG. 28 is a fragmentary perspective view of the stent graft of FIG. 1with various orientations of radiopaque markers according to theinvention;

FIG. 29 is a perspective view of a distal apex head of the apex capturedevice of FIG. 13;

FIG. 30 is a fragmentary side elevational view of the distal apex headof FIG. 29 and a proximal apex body of the apex capture device of FIG.13 with portions of a bare stent in the captured position;

FIG. 31 is a fragmentary, side elevational view of the distal apex headand proximal apex body of FIG. 30 with a portion of the proximal apexbody cut away to illustrate the bare stent in the captured position;

FIG. 32 is a fragmentary side elevational view of the distal apex headand proximal apex body of FIG. 30 in the released position;

FIG. 33 is a fragmentary, cross-sectional view of an embodiment ofhandle assemblies according to the invention;

FIG. 34 is a cross-sectional view of a pusher clasp rotator of thehandle assembly of FIG. 33;

FIG. 35 is a plan view of the pusher clasp rotator of FIG. 34 viewedalong line C-C;

FIG. 36 is a plan and partially hidden view of the pusher clasp rotatorof FIG. 34 with a helix groove for a first embodiment of the handleassembly of FIGS. 10, 11, and 18;

FIG. 37 is a cross-sectional view of the pusher clasp rotator of FIG. 36along section line A-A;

FIG. 38 is a plan and partially hidden view of the pusher clasp rotatorof FIG. 36;

FIG. 39 is a cross-sectional view of the pusher clasp rotator of FIG. 38along section line B-B;

FIG. 40 is a perspective view of a rotator body of the handle assemblyof FIG. 33;

FIG. 41 is an elevational and partially hidden side view of the rotatorbody of FIG. 40;

FIG. 42 is a cross-sectional view of the rotator body of FIG. 41 alongsection line A-A;

FIG. 43 is an elevational and partially hidden side view of the rotatorbody of FIG. 40;

FIG. 44 is an elevational and partially hidden side view of a pusherclasp body of the handle assembly of FIG. 33;

FIG. 45 is a cross-sectional view of the pusher clasp body of FIG. 44along section line A-A;

FIG. 46 is a cross-sectional view of the pusher clasp body of FIG. 44along section line B-B;

FIG. 47 is a fragmentary, side elevational view of a portion of thehandle assembly of FIG. 33 with a sheath assembly according to theinvention;

FIG. 48 is an exploded side elevational view of a portion of the handleassembly of FIG. 47;

FIG. 49 is a fragmentary elevational and partially hidden side view of ahandle body of the handle assembly of FIG. 33;

FIG. 50 is a fragmentary, exploded side elevational view of a portion ofa second embodiment of the handle assembly according to the invention;

FIG. 51 is a fragmentary, side elevational view of the portion of FIG.50 in a neutral position;

FIG. 52 is an exploded view of a first portion of the second embodimentof the handle assembly;

FIG. 53 is a fragmentary, exploded view of a larger portion of thesecond embodiment of the handle assembly as compared to FIG. 52 with thefirst portion and the sheath assembly;

FIG. 54 is perspective view of a clasp body of the second embodiment ofthe handle assembly;

FIG. 55 is an elevational side view of the clasp body of FIG. 54;

FIG. 56 is a cross-sectional view of the clasp body of FIG. 55 alongsection line A-A;

FIG. 57 is a plan view of the clasp body of FIG. 54;

FIG. 58 is a plan view of the clasp body of FIG. 57 viewed from sectionline B-B;

FIG. 59 is a fragmentary and partially hidden side elevational view of aclasp sleeve of the second embodiment of the handle assembly;

FIG. 60 is a fragmentary, cross-sectional view of a portion the claspsleeve of FIG. 59 along section line A;

FIG. 61 is a fragmentary, cross-sectional view of the clasp sleeve ofFIG. 59 along section line C-C;

FIG. 62 is a fragmentary and partially hidden side elevational view ofthe clasp sleeve of FIG. 59 rotated with respect to FIG. 59; and

FIG. 63 is a fragmentary, cross-sectional view of the nose cone andsheath assemblies of FIG. 10.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

While the specification concludes with claims defining the features ofthe invention that are regarded as novel, it is believed that theinvention will be better understood from a consideration of thefollowing description in conjunction with the drawing figures, in whichlike reference numerals are carried forward.

The present invention provides a stent graft and delivery system thattreats, in particular, thoracic aortic defects from the brachiocephaliclevel of the aortic arch distally to a level just superior to the celiacaxis and provides an endovascular foundation for an anastomosis with thethoracic aorta, while providing an alternative method for partial/totalthoracic aortic repair by excluding the vessel defect and makingsurgical repair of the aorta unnecessary. The stent graft of the presentinvention, however, is not limited to use in the aorta. It can beendoluminally inserted in any accessible artery that could accommodatethe stent graft's dimensions.

Stent Graft

The stent graft according to the present invention provides variousfeatures that, heretofore, have not been applied in the art and,thereby, provide a vessel repair device that implants/conforms moreefficiently within the natural or diseased course of the aorta,decreases the likelihood of vessel puncture, and increases theblood-tight vascular connection, and decreases the probability of graftmobility.

The stent graft is implanted endovascularly before or during or in placeof an open repair of the vessel (i.e., an arch, in particular, theascending and/or descending portion of the aorta) through a deliverysystem described in detail below. The typical defects treated by thestent graft are aortic aneurysms, aortic dissections, and other diseasessuch as penetrating aortic ulcer, coarctation, and patent ductusarteriosus, related to the aorta. When endovascularly placed in theaorta, the stent graft forms a seal in the vessel and automaticallyaffixes itself to the vessel with resultant effacement of thepathological lesion.

Referring now to the figures of the drawings in detail and first,particularly to FIG. 1 thereof, there is shown an improved stent graft 1having a graft sleeve 10 and a number of stents 20. These stents 20 are,preferably, made of nitinol, an alloy having particularly specialproperties allowing it to rebound to a set configuration aftercompression, the rebounding property being based upon the temperature atwhich the alloy exists. For a detailed explanation of nitinol and itsapplication with regard to stents, see, e.g., U.S. Pat. Nos. 4,665,906,5,067,957, and 5,597,378 to Jervis and to Gianturco.

The graft sleeve 10 is cylindrical in shape and is made of a woven graftmaterial along its entire length. The graft material is, preferably,polyester, in particular, polyester referred to under the name DACRON®or other material types like Expanded Polytetrafluoroethylene (“EPTFE”),or other polymeric based coverings. The tubular graft sleeve 10 has aframework of individual lumen-supporting wires each referred to in theart as a stent 20. Connection of each stent 20 is, preferably, performedby sewing a polymeric (nylon, polyester) thread around an entirety ofthe stent 20 and through the graft sleeve 10. The stitch spacings aresufficiently close to prevent any edge of the stent 20 from extendingsubstantially further from the outer circumference of the graft sleeve10 than the diameter of the wire itself. Preferably, the stitches have a0.5 mm to 5 mm spacing.

The stents 20 are sewn either to the exterior or interior surfaces ofthe graft sleeve 10. FIG. 1 illustrates all stents 20, 30 on theexterior surface 16 of the graft sleeve 10. In a preferrednon-illustrated embodiment, the most proximal 23 and distal stents and abare stent 30 are connected to the interior surface of the graft sleeve10 and the remainder of the stents 20 are connected to the exteriorsurface 16. Another possible non-illustrated embodiment alternatesconnection of the stents 20, 30 to the graft sleeve 10 from the graftexterior surface to the graft interior surface, the alternation havingany periodic sequence.

A stent 20, when connected to the graft sleeve 10, radially forces thegraft sleeve 10 open to a predetermined diameter D. The released radialforce creates a seal with the vessel wall and affixes the graft to thevessel wall when the graft is implanted in the vessel and is allowed toexpand.

Typically, the stents 20 are sized to fully expand to the diameter D ofthe fully expanded graft sleeve 10. However, a characteristic of thepresent invention is that each of the stents 20 and 30 has a diameterlarger than the diameter D of the fully expanded graft sleeve 10. Thus,when the stent graft 1 is fully expanded and resting on the internalsurface of the vessel where it has been placed, each stent 20 isimparting independently a radially directed force to the graft sleeve10. Such pre-compression, as it is referred to herein, is applied (1) toensure that the graft covering is fully extended, (2) to ensuresufficient stent radial force to make sure sealing occurs, (3) to affixthe stent graft and prevent it from kinking, and (4) to affix the stentgraft and prevent migration.

Preferably, each of the stents 20 is formed with a single nitinol wire.Of course other biocompatible materials can be used, for example,stainless steel, biopolymers, cobalt chrome, and titanium alloys.

The preferred shape of each stent 20 corresponds to what is referred inthe art as a Z-stent, see, e.g., Gianturco (although the shape of thestents 20 can be in any form that satisfies the functions of aself-expanding stent). Thus, the wire forming the stent 20 is a ringhaving a wavy or sinusoidal shape. In particular, an elevational vieworthogonal to the center axis 21 of the stent 20 reveals a shapesomewhere between a triangular wave and a sinusoidal wave as shown inFIG. 2. In other words, the view of FIG. 2 shows that the stents 20 eachhave alternating proximal 22 and distal 24 apices. Preferably, theapices have a radius r that does not present too great of a pointtowards a vessel wall to prevent any possibility of puncturing thevessel, regardless of the complete circumferential connection to thegraft sleeve 10. In particular, the radius r of curvature of theproximal 22 and distal 24 apices of the stent 20 are, preferably, equal.The radius of curvature r is between approximately 0.1 mm andapproximately 3.0 mm, in particular, approximately 0.5 mm.

Another advantageous feature of a stent lies in extending thelongitudinal profile along which the stent contacts the inner wall of avessel. This longitudinal profile can be explained with reference toFIGS. 3 to 7.

Prior art stents and stents according to the present invention areformed on mandrels 29, 29′ by winding the wire around the mandrel 29,29′ and forming the apexes 22, 24, 32, 34 by wrapping the wire overnon-illustrated pins that protrude perpendicular from the axis of themandrel. Such pins, if illustrated, would be located in the holesillustrated in the mandrels 29, 29′ of FIGS. 4 and 6. Prior art stentsare formed on a round mandrel 29 (also referred to as a bar). A stent20′ formed on a round mandrel 29 has a profile that is rounded (see FIG.5). Because of the rounded profile, the stent 20′ does not conformevenly against the inner wall of the vessel 2 in which it is inserted.This disadvantage is critical in the area of stent graft 1 sealzones—areas where the ends of the graft 10 need to be laid against theinner wall of the vessel 2. Clinical experience reveals that stents 20′formed with the round mandrel 29 do not lie against the vessel 2;instead, only a mid-section of the stent 20′ rests against the vessel 2,as shown in FIG. 5. Accordingly, when such a stent 20′ is present ateither of the proximal 12 or distal 14 ends of the stent graft 1, thegraft material flares away from the wall of the vessel 2 into thelumen—a condition that is to be avoided. An example of this flaring canbe seen by comparing the upper and lower portions of the curvedlongitudinal profile of the stent 20′ in FIG. 5 with the linearlongitudinal profile of the vessel 2.

To remedy this problem and ensure co-columnar apposition of the stentand vessel, stents 20 of the present invention are formed on amultiple-sided mandrel. In particular, the stents 20 are formed on apolygonal-shaped mandrel 29′. The mandrel 29′ does not have sharp edges.Instead, it has flat sections and rounded edge portions between therespective flat sections. Thus, a stent formed on the mandrel 29′ willhave a cross-section that is somewhat round but polygonal, as shown inFIG. 3. The cross-sectional view orthogonal to the center axis 21 ofsuch a stent 20 will have beveled or rounded edges 31 (corresponding tothe rounded edge portions of the mandrel 29′) disposed between flatsides or struts 33 (corresponding to the flat sections of the mandrel29′). With stents manufactured in this way, the apices remain on thecircumference of the graft and do not bend into the graft interior likeprior art stents—an undesirable condition as explained in the precedingparagraph. Further, the struts of the stents so manufactured (thesubstantially linear portions of the stent between the apices) lie inthe plane of the graft material when attached thereto as shown in FIG.7. In contrast, prior art struts are curved (see FIG. 5) and, therefore,force the graft material inwards away from the vessel wall. As usedherein, substantially linear means that the struts are sufficientlystraight and level to substantially prevent displacement of an apex(which lies between two adjacent struts) towards the interior of thegraft material to which the struts and apices are attached.

To manufacture the stent 20, apexes of the stents 20 are formed bywinding the wire over non-illustrated pins located on the roundedportions of the mandrel 29′. Thus, the struts 33 lying between theapexes 22, 24, 32, 34 of the stents 20 lie flat against the flat sidesof the mandrel 29′. When so formed on the inventive mandrel 29′, thelongitudinal profile is substantially less rounded than the profile ofstent 20′ and, in practice, is substantially linear.

For stents 20 having six proximal 22 and six distal 24 apices, thestents 20 are formed on a dodecahedron-shaped mandrel 29′ (a mandrelhaving twelve sides), which mandrel 29′ is shown in FIG. 6. A stent 20formed on such a mandrel 29′ will have the cross-section illustrated inFIG. 3.

The fourteen-apex stent 20 shown in FIG. 7 illustrates a stent 20 thathas been formed on a fourteen-sided mandrel. The stent 20 in FIG. 7 ispolygonal in cross-section (having fourteen sides) and, as shown in FIG.7, has a substantially linear longitudinal profile. Clinically, thelinear longitudinal profile improves the stent's 20 ability to conformto the vessel 2 and press the graft sleeve 10 outward in the sealingzones at the extremities of the individual stent 20.

Another way to improve the performance of the stent graft 1 is toprovide the distal-most stent 25 on the graft 10 (i.e., downstream) withadditional apices and to give it a longer longitudinal length (i.e.,greater amplitude) and/or a longer circumferential length. When a stent25 having a longer circumferential length is sewn to a graft, the stentgraft 1 will perform better clinically. The improvement, in part, is dueto a need for the distal portion of the graft material 10 to be pressedfirmly against the wall of the vessel. The additional apices result inadditional points of contact between the stent graft 1 and vessel wall,thus ensuring better apposition to the wall of the vessel and bettersealing of the graft material 10 to the vessel. The increased appositionand sealing substantially improves the axial alignment of the distal end14 of the stent graft 1 to the vessel. As set forth above, each of thestents 20 and 30 has a diameter larger than the diameter D of the fullyexpanded graft sleeve 10. Thus, if the distal stent 25 also has adiameter larger than the diameter D, it will impart a greater radialbias on all 360 degrees of the corresponding section of the graft thanstents not having such an oversized configuration.

A typical implanted stent graft 1 typically does not experience alifting off at straight portions of a vessel because the radial bias ofthe stents acting upon the graft sleeve give adequate pressure to alignthe stent and graft sleeve with the vessel wall. However, when a typicalstent graft is implanted in a curved vessel (such as the aorta), thedistal end of the stent graft 1 does experience a lift off from thevessel wall. The increased apposition and sealing of the stent graft 1according to the present invention substantially decreases theprobability of lift off because the added height and additional apicesenhance the alignment of the stent graft perpendicular to the vesselwall as compared to prior art stent grafts (no lift off occurs). Thenumber of total apices of a stent is dependent upon the diameter of thevessel in which the stent graft 1 is to be implanted. Vessels having asmaller diameter have a smaller total number of apices than a stent tobe implanted in a vessel having a larger diameter. Table 1 belowindicates preferred stent embodiments for vessels having differentdiameters. For example, if a vessel has a 26 or 27 mm diameter, then apreferred diameter of the graft sleeve 10 is 30 mm. For a 30 mm diametergraft sleeve, the intermediate stents 20 will have 5 apices on each side(proximal and distal) for a total of 10 apices. In other words, thestent defines 5 periodic “waves.” The distal-most stent 25, incomparison, defines 6 periodic “waves” and, therefore, has 12 totalapices. It is noted that the distal-most stent 25 in FIG. 1 does nothave the additional apex. While Table 1 indicates preferred embodiments,these configurations can be adjusted or changed as needed.

TABLE 1 Stent Apices/Side Vessel Diameter (mm) Graft Diameter (mm)(Distal-most Stent #) 19 22 5(5) 20-21 24 5(5) 22-23 26 5(5) 24-25 285(6) 26-27 30 5(6) 28-29 32 6(7) 30-31 34 6(7) 32-33 36 6(7) 34 38 6(7)35-36 40 7(8) 37-38 42 7(8) 39-40 44 7(8) 41-42 46 7(8)

To increase the security of the stent graft 1 in a vessel, an exposed orbare stent 30 is provided on the stent graft 1, preferably, only at theproximal end 12 of the graft sleeve 10—proximal meaning that it isattached to the portion of the graft sleeve 10 from which the bloodflows into the sleeve, i.e., blood flows from the bare stent 30 andthrough the sleeve 10 to the left of FIG. 1. The bare stent 30 is notlimited to being attached at the proximal end 12. Anothernon-illustrated bare stent can be attached similarly to the distal end14 of the graft sleeve 10.

Specifically, the bare stent 30 is fixed to the graft sleeve 10 only atthe distal apices 34 of the bare stent 30. Thus, the bare stent 30 ispartially free to extend the proximal apices 32 away from the proximalend of the graft sleeve 10.

The bare stent 30 has various properties, the primary one being toimprove the apposition of the graft material to the contour of thevessel wall and to align the proximal portion of the graft covering inthe lumen of the arch and provide a blood-tight closure of the proximalend 12 of the graft sleeve 10 so that blood does not pass between thevascular inside wall and outer surface 16 of the sleeve 10 (endoleak).

The preferred configuration for the radius of curvature a of the distalapices 34 is substantially equal to the radius r of the proximal 22 anddistal 24 apices of the stent 20, in particular, it is equal at least tothe radius of curvature r of the proximal apices of the stent 20directly adjacent the bare stent 30. Thus, as shown in FIG. 8, adistance between the proximal apices 22 of the most proximal stent 23and crossing points of the exposed portions of the bare stent 30 aresubstantially at a same distance from one another all the way around thecircumference of the proximal end 12 of the graft sleeve 10. Preferably,this distance varies based upon the graft diameter. Accordingly, thesinusoidal portion of the distal apices 34 connected to the graft sleeve10 traverse substantially the same path as that of the stent 23 closestto the bare stent 30. Thus, the distance d between the stent 22 and allportions of the bare stent 30 connected to the graft sleeve 10 remainconstant. Such a configuration is advantageous because it maintains thesymmetry of radial force of the device about the circumference of thevessel and also aids in the synchronous, simultaneous expansion of thedevice, thus increasing apposition of the graft material to the vesselwall to induce a proximal seal—and substantially improve the proximalseal—due to increasing outward force members in contact with the vesselwall.

Inter-positioning the stents 23, 30 in phase with one another, createsan overlap, i.e., the apices 34 of the bare stent 30 are positionedwithin the troughs of the stent 23. A further advantage of such aconfiguration is that the overlap provides twice as many points ofcontact between the proximal opening of the graft 10 and the vessel inwhich the stent graft 1 is implanted. The additional apposition pointskeep the proximal opening of the graft sleeve 10 open against the vesselwall, which substantially reduces the potential for endoleaks. Inaddition, the overlap of the stents 23, 30 increases the radial load orresistance to compression, which functionally increases fixation andreduces the potential for device migration.

In contrast to the distal apices 34 of the bare stent 30, the radius ofcurvature 13 of the proximal apices 32 (those apices that are not sewninto the graft sleeve 10) is significantly larger than the radius ofcurvature a of the distal apices 34. A preferred configuration for thebare stent apices has a radius approximately equal to 1.5 mm for theproximal apices 32 and approximately equal to 0.5 mm for the distalapices 34. Such a configuration substantially prevents perforation ofthe blood vessel by the proximal apices 32, or, at a minimum, makes ismuch less likely for the bare stent 30 to perforate the vessel becauseof the less-sharp curvature of the proximal apices 32.

The bare stent 30 also has an amplitude greater than the other stents20. Preferably, the peak-to-peak amplitude of the stents 20 isapproximately 1.3 cm to 1.5 cm, whereas the peak-to-peak amplitude ofthe bare stent 30 is approximately 2.5 cm to 4.0 cm. Accordingly, theforce exerted by the bare stent 30 on the inner wall of the aorta (dueto the bare stent 30 expanding to its native position) is spread over alarger surface area. Thus, the bare stent 30 of the present inventionpresents a less traumatic radial stress to the interior of the vesselwall—a characteristic that, while less per square mm than an individualone of the stents 20 would be, is sufficient, nonetheless, to retain theproximal end 12 in position. Simultaneously, the taller configuration ofthe bare stent 30 guides the proximal opening of the stent graft in amore “squared-off” manner. Thus, the proximal opening of the stent graftis more aligned with the natural curvature of the vessel in the area ofthe proximal opening.

As set forth above, because the vessel moves constantly, and due to theconstantly changing pressure imparted by blood flow, any stent graftplaced in the vessel has the natural tendency to migrate downstream.This is especially true when the stent graft 1 has graft sleeve segments18 with lengths defined by the separation of the stents on either end ofthe segment 18, giving the stent graft 1 an accordion, concertina, orcaterpillar-like shape. When such a shape is pulsating with the vesseland while hemodynamic pressure is imparted in a pulsating manner alongthe stent graft from the proximal end 12 to the downstream distal end14, the stent graft 1 has a tendency to migrate downstream in thevessel. It is desired to have such motion be entirely prohibited.

Support along a longitudinal extent of the graft sleeve 10 assists inpreventing such movement. Accordingly, as set forth above, prior artstent grafts have provided longitudinal rods extending in a straightline from one stent to another.

The present invention, however, provides a longitudinal,spiraling/helical support member 40 that, while extending relativelyparallel to the longitudinal axis 11 of the graft sleeve 10, is notaligned substantially parallel to a longitudinal extent of the entiretyof the stent graft 1 as done in the prior art. “Relatively parallel” isreferred to herein as an extent that is more along the longitudinal axis11 of the stent graft 1 than along an axis perpendicular thereto.

Specifically, the longitudinal support member 40 has a somewhat S-turnshape, in that, a proximal portion 42 is relatively parallel to the axis11 of the graft sleeve 10 at a first degree 41 (being defined as adegree of the 360 degrees of the circumference of the graft sleeve 10),and a distal portion 44 is, also, relatively parallel to the axis 11 ofthe tube graft, but at a different second degree 43 on the circumferenceof the graft sleeve 10. The difference between the first and seconddegrees 41, 43 is dependent upon the length L of the graft sleeve 10.For an approximately 20 cm (approx. 8″) graft sleeve, for example, thesecond degree 43 is between 80 and 110 degrees away from the firstdegree 41, in particular, approximately 90 degrees away. In comparison,for an approximately 9 cm (approx. 3.5″) graft sleeve, the second degree43 is between 30 and 60 degrees away from the first degree 41, inparticular, approximately 45 degrees away. As set forth below, thedistance between the first and second degrees 41, 43 is also dependentupon the curvature and the kind of curvature that the stent graft 1 willbe exposed to when in vivo.

The longitudinal support member 40 has a curved intermediate portion 46between the proximal and distal portions 42, 44. By using the word“portion” it is not intended to mean that the rod is in three separateparts (of course, in a particular configuration, a multi-part embodimentis possible). A preferred embodiment of the longitudinal support member40 is a single, one-piece rod made of stainless steel, cobalt chrome,nitinol, or polymeric material that is shaped as a fully curved helix42, 44, 46 without any straight portion. In an alternative stent graftembodiment, the proximal and distal portions 42, 44 can be substantiallyparallel to the axis 11 of the stent graft 1 and the central portion 46can be helically curved.

One way to describe the preferred curvature embodiment of thelongitudinal support member 40 can be using an analogy of asymptotes. Ifthere are two asymptotes extending parallel to the longitudinal axis 11of the graft sleeve 10 at the first and second degrees 41, 43 on thegraft sleeve 10, then the proximal portion 42 can be on the first degree41 or extend approximately asymptotically to the first degree 41 and thedistal portion 44 can be on the second degree 43 or extend approximatelyasymptotically to the second degree 43. Because the longitudinal supportmember 40 is one piece in a preferred embodiment, the curved portion 46follows the natural curve formed by placing the proximal and distalportions 42, 44 as set forth herein.

In such a position, the curved longitudinal support member 40 has acenterline 45 (parallel to the longitudinal axis 11 of the graft sleeve10 halfway between the first and second degrees 41, 43 on the graftsleeve 10). In this embodiment, therefore, the curved portion intersectsthe centerline 45 at approximately 20 to 40 degrees in magnitude,preferably at approximately 30 to 35 degrees.

Another way to describe the curvature of the longitudinal support membercan be with respect to the centerline 45. The portion of thelongitudinal support member 40 between the first degree 41 and thecenterline 45 is approximately a mirror image of the portion of thelongitudinal support member 40 between the second degree 43 and thecenterline 45, but rotated 180 degrees around an axis orthogonal to thecenterline 45. Such symmetry can be referred to herein as“reverse-mirror symmetrical.”

The longitudinal support member 40 is, preferably, sewn to the graftsleeve 10 in the same way as the stents 20. However, the longitudinalsupport member 40 is not sewn directly to any of the stents 20 in theproximal portions of the graft. In other words, the longitudinal supportmember 40 is independent of the proximal skeleton formed by the stents20. Such a configuration is advantageous because an independent proximalend creates a gimbal that endows the stent graft with additionalflexibility. Specifically, the gimbaled proximal end allows the proximalend to align better to the proximal point of apposition, thus reducingthe chance for endoleak. The additional independence from thelongitudinal support member allows the proximal fixation point to beindependent from the distal section that is undergoing related motiondue to the physiological motion of pulsutile flow of blood. Also in apreferred embodiment, the longitudinal support member 40 is pre-formedin the desired spiral/helical shape (counter-clockwise from proximal todistal), before being attached to the graft sleeve 10.

Because vessels receiving the stent graft 1 are not typically straight,the final implanted position of the stent graft 1 will, most likely, becurved in some way. In prior art stent grafts (which only providelongitudinally parallel support rods), there exist, inherently, a forcethat urges the rod, and, thereby, the entire stent graft, to thestraightened, natural shape of the rod. This force is disadvantageousfor stent grafts that are to be installed in an at least partly curvedmanner.

The curved shape of the longitudinal support member 40 according to thepresent invention eliminates at least a majority, or substantially all,of this disadvantage because the longitudinal support member's 40natural shape is curved and, therefore, imparts less of a force, or noneat all, to straighten the longitudinal support member 40, and, thereby,move the implanted stent graft in an undesirable way. At the same time,the curved longitudinal support member 40 negates the effect of thelatent kinetic force residing in the aortic wall that is generated bythe propagation of the pulse wave and systolic blood pressure in thecardiac cycle, which is, then, released during diastole.

In a preferred embodiment, the longitudinal support member 40 can becurved in a patient-customized way to accommodate the anticipated curveof the actual vessel in which the graft will be implanted. Thus, thedistance between the first and second degrees 41, 43 will be dependentupon the curvature and the kind of curvature that the stent graft 1 willbe exposed to when in vivo. As such, when implanted, the curvedlongitudinal support member 40 will, actually, exhibit an opposite forceagainst any environment that would alter its conformance to the shape ofits resident vessel's existing course(es).

Preferably, the support member 40 is sewn, in a similar manner as thestents 20, on the outside surface 16 of the graft sleeve 10.

In prior art support rods, the ends thereof are merely a terminating endof a steel or nitinol rod and are, therefore, sharp. Even though theseends are sewn to the tube graft in the prior art, the possibility oftearing the vessel wall still exists. It is, therefore, desirable to notprovide the support rod with sharp ends that could puncture the vesselin which the stent graft is placed.

The two ends of the longitudinal support member 40 of the presentinvention do not end abruptly. Instead, each end of the longitudinalsupport member loops 47 back upon itself such that the end of thelongitudinal support member along the axis of the stent graft is notsharp and, instead, presents an exterior of a circular or oval shapewhen viewed from the ends 12, 14 of the graft sleeve 10. Such aconfiguration substantially prevents the possibility of tearing thevessel wall and also provides additional longitudinal support at theoval shape by having two longitudinally extending sides of the oval 47.

In addition, in another embodiment, the end of the longitudinal supportmember may be connected to the second proximal stent 28 and to the mostdistal stent. This configuration would allow the longitudinal supportmember to be affixed to stent 28 (see FIG. 1) and the most distal stentfor support while still allowing for the gimbaled feature of theproximal end of the stent graft to be maintained.

A significant feature of the longitudinal support member 40 is that theends of the longitudinal support member 40 may not extend all the way tothe two ends 12, 14 of the graft sleeve 10. Instead, the longitudinalsupport member 40 terminates at or prior to the second-to-last stent 28at the proximal end 12, and, if desired, prior to the second-to-laststent 28′ at the distal end 14 of the graft sleeve 10. Such an endingconfiguration (whether proximal only or both proximal and distal) ischosen for a particular reason—when the longitudinal support member 40ends before either of the planes defined by cross-sectional lines 52,52′, the sleeve 10 and the stents 20 connected thereto respectively formgimbaled portions 50, 50′. In other words, when a grasping force actingupon the gimbaled ends 50, 50′ moves or pivots the cross-sectional planedefining each end opening of the graft sleeve 10 about the longitudinalaxis 11 starting from the planes defined by the cross-sectional lines52, 52′, then the moving portions 50, 50′ can be oriented at any angle γabout the center of the circular opening in all directions (360degrees), as shown in FIG. 8. The natural gimbal, thus, allows the ends50, 50′ to be inclined in any radial direction away from thelongitudinal axis 11.

Among other things, the gimbaled ends 50, 50′ allow each end opening todynamically align naturally to the curve of the vessel in which it isimplanted. A significant advantage of the gimbaled ends 50, 50′ is thatthey limit propagation of the forces acting upon the separate parts.Specifically, a force that, previously, would act upon the entirety ofthe stent graft 1, in other words, both the end portions 50, 50′ and themiddle portion of the stent graft 1 (i.e., between planes 52, 52′), nowprincipally acts upon the portion in which the force occurs. Forexample, a force that acts only upon one of the end portions 50, 50′substantially does not propagate into the middle portion of the stentgraft 1 (i.e., between planes 52, 52′). More significantly, however,when a force acts upon the middle portion of the stent graft 1 (whethermoving longitudinally, axially (dilation), or in a torqued manner), theends 50, 50′, because they are gimbaled, remain relatively completelyaligned with the natural contours of the vessel surrounding therespective end 50, 50′ and have virtually none of the force transferredthereto, which force could potentially cause the ends to grate, rub, orshift from their desired fixed position in the vessel.

Accordingly, the stent graft ends 50, 50′ remain fixed in the implantedposition and extend the seating life of the stent graft 1.

Another advantage of the longitudinal support member 40 is that itincreases the columnar strength of the graft stent 1. Specifically, thematerial of the graft sleeve can be compressed easily along thelongitudinal axis 11, a property that remains true even with thepresence of the stents 20 so long as the stents 20 are attached to thegraft sleeve 10 with a spacing between the distal apices 24 of one stent20 and the proximal apices 22 of the next adjacent stent 20. This isespecially true for the amount of force imparted by the flow of bloodalong the extent of the longitudinal axis 11. However, with thelongitudinal support member 40 attached according to the presentinvention, longitudinal strength of the stent graft 1 increases toovercome the longitudinal forces imparted by blood flow.

Another benefit imparted by having such increased longitudinal strengthis that the stent graft 1 is further prevented from migrating in thevessel because the tube graft is not compressing and expanding in anaccordion-like manner—movement that would, inherently, cause graftmigration.

A further measure for preventing migration of the stent graft 1 is toequip at least one of any of the individual stents 20, 30 or thelongitudinal support member 40 with protuberances 60, such as barbs orhooks (FIG. 3). See, e.g., United States Patent Publication 2002/0052660to Greenhalgh. In the preferred embodiment of the present invention, thestents 20, 30 are secured to the outer circumferential surface 16 of thegraft sleeve 10. Accordingly, if the stents 20 (or connected portions ofstent 30) have protuberances 60 protruding outwardly, then such featureswould catch the interior wall of the vessel and add to the prevention ofstem graft 1 migration. Such an embodiment can be preferred foraneurysms but is not preferred for the fragile characteristics ofdissections because such protuberances 60 can excoriate the innerlayer(s) of the vessel and cause leaks between layers, for example.

As shown in FIG. 9, the stent graft 1 is not limited to a single graftsleeve 10. Instead, the entire stent graft can be a first stent graft100 having all of the features of the stent graft 1 described above anda second stent graft 200 that, instead of having a circular extremeproximal end 12, as set forth above, has a proximal end 212 with a shapefollowing the contour of the most proximal stent 220 and is slightlylarger in circumference than the distal circumference of the first stentgraft 100. Therefore, an insertion of the proximal end 212 of the secondstent graft 200 into the distal end 114 of the first stent graft 100results, in total, in a two-part stent graft. Because blood flows fromthe proximal end 112 of the first stent graft 100 to the distal end 214of the second stent graft 200, it is preferable to have the first stentgraft 100 fit inside the second stent graft 200 to prevent blood fromleaking out therebetween. This configuration can be achieved byimplanting the devices in reverse order (first implant graft 200 and,then, implant graft 100. Each of the stent grafts 100, 200 can have itsown longitudinal support member 40 as needed.

It is not significant if the stent apices of the distal-most stent ofthe first stent graft 100 are not aligned with the stent apices of theproximal-most stent 220 of the second stent graft 200. What is importantis the amount of junctional overlap between the two grafts 100, 200.

Delivery System

As set forth above, the prior art includes many different systems forendoluminally delivering a prosthesis, in particular, a stent graft, toa vessel. Many of the delivery systems have similar parts and most areguided along a guidewire that is inserted, typically, through aninsertion into the femoral artery near a patient's groin prior to use ofthe delivery system. To prevent puncture of the arteries leading to andincluding the aorta, the delivery system is coaxially connected to theguidewire and tracks the course of the guidewire up to the aorta. Theparts of the delivery system that will track over the wire are,therefore, sized to have an outside diameter smaller than the insidediameter of the femoral artery of the patient. The delivery systemcomponents that track over the guidewire include the stent graft and aremade of a series of coaxial lumens referred to as catheters and sheaths.The stent graft is constrained, typically, by an outer catheter,requiring the stent graft to be compressed to fit inside the outercatheter. Doing so makes the portion of the delivery system thatconstrains the stent graft very stiff, which, therefore, reduces thatportion's flexibility and makes it difficult for the delivery system totrack over the guidewire, especially along curved vessels such as theaortic arch. In addition, because the stent graft exerts very highradial forces on the constraining catheter due to the amount that itmust be compressed to fit inside the catheter, the process of deployingthe stent graft by sliding the constraining catheter off of the stentgraft requires a very high amount of force, typically referred to as adeployment force. Also, the catheter has to be strong enough toconstrain the graft, requiring it to be made of a rigid material. If therigid material is bent, such as when tracking into the aortic arch, therigid material tends to kink, making it difficult if not impossible todeploy the stent graft.

Common features of vascular prosthesis delivery systems include atapered nose cone fixedly connected to a guidewire lumen, which has aninner diameter substantially corresponding to an outer diameter of theguidewire such that the guidewire lumen slides easily over and along theguidewire. A removable, hollow catheter covers and holds a compressedprosthesis in its hollow and the catheter is fixedly connected to theguidewire lumen. Thus, when the prosthesis is in a correct position forimplantation, the physician withdraws the hollow catheter to graduallyexpose the self-expanding prosthesis from its proximal end towards itsdistal end. When the catheter has withdrawn a sufficient distance fromeach portion of the expanding framework of the prosthesis, the frameworkcan expand to its native position, preferably, a position that has adiameter at least as great as the inner diameter of the vessel wall to,thereby, tightly affix the prosthesis in the vessel. When the catheteris entirely withdrawn from the prosthesis and, thereby, allows theprosthesis to expand to the diameter of the vessel, the prosthesis isfully expanded and connected endoluminally to the vessel along theentire extent of the prosthesis, e.g., to treat a dissection. Whentreating an aneurysm, for example, the prosthesis is in contact with thevessel's proximal and distal landing zones when completely released fromthe catheter. At such a point in the delivery, the delivery system canbe withdrawn from the patient. The prosthesis, however, cannot bereloaded in the catheter if implantation is net optimal.

The aorta usually has a relatively straight portion in the abdominalregion and in a lower part of the thoracic region. However, in the upperpart of the thoracic region, the aorta is curved substantially,traversing an upside-down U-shape from the back of the heart over to thefront of the heart. As explained above, prior art delivery systems arerelatively hard and inflexible (the guidewire/catheter portion of theprior art delivery systems). Therefore, if the guidewire/catheter musttraverse the curved portion of the aorta, it will kink as it is curvedor it will press against the top portion of the aortic curve, possiblypuncturing the aorta if the diseased portion is located where theguidewire/catheter is exerting its force. Such a situation must beavoided at all costs because the likelihood of patient mortality ishigh. The prior art does not provide any way for substantially reducingthe stress on the curved portion of the aorta or for making theguidewire/catheter sufficiently flexible to traverse the curved portionwithout causing damage to the vessel.

The present invention, however, provides significant features not foundin the prior art that assist in placing a stent graft in a curvedportion of the aorta in a way that substantially reduces the stress onthe curved portion of the aorta and substantially reduces the insertionforces needed to have the compressed graft traverse the curved portionof the aorta. The delivery system of the present invention also has avery simple to use handle assembly. The handle assembly takes advantageof the fact that the inside diameter of the aorta is substantiallylarger that the inside diameter of the femoral arteries. The presentinvention, accordingly, uses a two-stage approach in which, after thedevice is inserted in through the femoral artery and tracks up into theabdominal area of the aorta (having a larger diameter (see FIG. 19) thanthe femoral artery), a second stage is deployed (see FIG. 20) allowing asmall amount of expansion of the stent graft while still constrained ina sheath; but this sheath, made of fabric/woven polymer or similarflexible material, is very flexible. Such a configuration gives thedelivery system greater flexibility for tracking, reduces deploymentforces because of the larger sheath diameter, and easily overcome kinksbecause the sheath is made of fabric.

To describe the delivery system of the present invention, the method foroperating the delivery assembly 600 will be described first inassociation with FIGS. 10, 11, and 12. Thereafter, the individualcomponents will be described to allow a better understanding of how eachstep in the process is effected for delivering the stent graft 1 to anyportion of the aorta 700 (see FIGS. 19 to 24), in particular, the curvedportion 710 of the aorta.

Initially, the distal end 14 of the stent graft 1 is compressed andplaced into a hollow, cup-shaped, or tubular-shaped graft holdingdevice, in particular, the distal sleeve 644 (see, e.g., FIG. 25). Atthis point, it is noted that the convention for indicating directionwith respect to delivery systems is opposite that of the convention forindicating direction with respect to stent grafts. Therefore, theproximal direction of the delivery system is that portion closest to theuser/physician employing the system and the distal direction correspondsto the portion farthest away from the user/physician, i.e., towards thedistal-most nose cone 632.

The distal sleeve 644 is fixedly connected to the distal end of thegraft push lumen 642, which lumen 642 provides an end face for thedistal end 14 of the stent graft 1. Alternatively, the distal sleeve 644can be removed entirely. In such a configuration, as shown in FIG. 12,for example, the proximal taper of the inner sheath 652 can provide themeasures for longitudinally holding the compressed distal end of thegraft 1. As set forth in more detail below, each apex 32 of the barestent 30 is, then, loaded into the apex capture device 634 so that thestent graft 1 is held at both its proximal and distal ends. The loadeddistal end 14, along with the distal sleeve 644 and the graft push lumen642, are, in turn, loaded into the inner sheath 652, thus, furthercompressing the entirety of the stent graft 1. The captured bare stent30, along with the nose cone assembly 630 (including the apex capturedevice 634), is loaded until the proximal end of the nose cone 632 restson the distal end of the inner sheath 652. The entire nose cone assembly630 and sheath assembly 650 is, then, loaded proximally into the rigidouter catheter 660, further compressing the stent graft 1 (restinginside the inner sheath 652) to its fully compressed position for laterinsertion into a patient. See FIG. 63.

The stent graft 1 is, therefore, held both at its proximal and distalends and, thereby, is both pushed and pulled when moving from a firstposition (shown in FIG. 19 and described below) to a second position(shown in FIG. 21 and described below). Specifically, pushing isaccomplished by the non-illustrated interior end face of the hollowdistal sleeve 644 (or the taper 653 of the inner sheath 652) and pullingis accomplished by the hold that the apex capture device 634 has on theapices 32 of the bare stent 30.

The assembly 600 according to the present invention tracks along aguidewire 610 already inserted in the patient and extending through theaorta and up to, but not into, the left ventricle of the heart 720.Therefore, a guidewire 610 is inserted through the guidewire lumen 620starting from the nose cone assembly 630, through the sheath assembly650, through the handle assembly 670, and through the apex releaseassembly 690. The guidewire 610 extends out the proximal-most end of theassembly 600. The guidewire lumen 620 is coaxial with the nose coneassembly 630, the sheath assembly 650, the handle assembly 670, and theapex release assembly 690 and is the innermost lumen of the assembly 600immediately surrounding the guidewire 610.

Before using the delivery system assembly 600, all air must be purgedfrom inside the assembly 600. Therefore, a liquid, such as sterileU.S.P. saline, is injected through a non-illustrated tapered luerfitting to flush the guidewire lumen at a non-illustrated purge portlocated near a proximal end of the guidewire lumen. Second, saline isalso injected through the luer fitting 612 of the lateral purge-port(see FIG. 11), which liquid fills the entire internal co-axial space ofthe delivery system assembly 600. It may be necessary to manipulate thesystem to facilitate movement of the air to be purged to the highestpoint of the system.

After purging all air, the system can be threaded onto the guidewire andinserted into the patient. Because the outer catheter 660 has apredetermined length, the fixed front handle 672 can be disposedrelatively close to the entry port of the femoral artery. It is noted,however, that the length of the outer catheter 660 is sized such that itwill not have the fixed proximal handle 672 directly contact the entryport of the femoral artery in a patient who has the longest distancebetween the entry port and the thoracic/abdominal junction 742, 732 ofthe aorta expected in a patient (this distance is predetermined). Thus,the delivery assembly 600 of the present invention can be used withtypical anatomy of the patient. Of course, the assembly 600 can be sizedto any usable length.

The nose cone assembly 630 is inserted into a patient's femoral arteryand follows the guidewire 610 until the nose cone 632 reaches the firstposition at a level of the celiac axis. The first position is shown inFIG. 19. The nose cone assembly 630 is radiopaque, whether wholly orpartially, to enable the physician to determine fluoroscopically, forexample, that the nose cone assembly 630 is in the first position. Forexample, the nose cone 632 can have a radiopaque marker 631 anywherethereon or the nose cone 632 can be entirely radiopaque.

After the nose cone assembly 630 is in the first position shown in FIG.19, the locking ring 676 is placed from its neutral position N, shown inFIG. 10, into its advancement position A, shown in FIG. 11. As will bedescribed below, placing the locking ring 676 into its advancementposition A allows both the nose cone assembly 630 and the internalsheath assembly 650 to move as one when the proximal handle 678 is movedin either the proximal or distal directions because the locking ring 676radially locks the graft push lumen 642 to the lumens of the apexrelease assembly 690 (including the guidewire lumen 620 and an apexrelease lumen 640). The locking ring 676 is fixedly connected to asheath lumen 654.

Before describing how various embodiments of the handle assembly 670function, a summary of the multi-lumen connectivity relationships,throughout the neutral N, advancement A, and deployment D positions, isdescribed.

When the locking ring is in the neutral position N shown in FIG. 10, thepusher clasp spring 298 shown in FIG. 48 and the proximal spring 606shown in FIG. 52 are both disengaged. This allows free movement of thegraft push lumen 642 with the guidewire lumen 620 and the apex releaselumen 640 within the handle body 674.

When the locking ring 676 is moved into the advancement position A,shown in FIG. 11, the pusher clasp spring 298 shown in FIG. 48 isengaged and the proximal spring 606 shown in FIG. 52 is disengaged. Thesheath lumen 654 (fixedly attached to the inner sheath 652) is, thereby,locked to the graft push lumen 642 (fixedly attached to the distalsleeve 644) so that, when the proximal handle 678 is moved toward thedistal handle 672, both the sheath lumen 654 and the graft push lumen642 move as one. At this point, the graft push lumen 642 is also lockedto both the guidewire lumen 620 and the apex release lumen 640 (whichare locked to one another through the apex release assembly 690 as setforth in more detail below). Accordingly, as the proximal handle 678 ismoved to the second position, shown with dashed lines in FIG. 11, thesheath assembly 650 and the nose cone assembly 630 progress distally outof the outer catheter 660 as shown in FIGS. 20 and 21 and with dashedlines in FIG. 11.

At this point, the sheath lumen 654 needs to be withdrawn from the stentgraft 1 to, thereby, expose the stent graft 1 from its proximal end 12to its distal end 14 and, ultimately, entirely off of its distal end 14.Therefore, movement of the locking ring 676 into the deployment positionD will engage the proximal spring 606 shown in FIG. 52 and disengage thepusher clasp spring 298 shown in FIG. 48. At this point, the graft pushlumen 642 along with the guidewire lumen 620 and the apex release lumen640 are locked to the handle body 674 so as not to move with respect tothe handle body 674. The sheath lumen 654 is unlocked from the graftpush lumen 642. Movement of the distal handle 678 back to the thirdposition (proximally), therefore, pulls the sheath lumen 654 proximally,thus, proximally withdrawing the inner sheath 652 from the stent graft1.

At this point, only the bare stent 30 of the stent graft 1 is held bythe delivery assembly 600. Therefore, final release of the stent graft 1occurs by releasing the bare stent 30 from the nose cone assembly 630,which is accomplished using the apex release assembly 690 as set forthbelow.

In order to explain how the locking and releasing of the lumen occur asset forth above, reference is made to FIGS. 33 to 62.

FIG. 33 is a cross-sectional view of the proximal handle 678 and thelocking ring 676. A pusher clasp rotator 292 is disposed between a claspsleeve 614 and the graft push lumen 642. A specific embodiment of thepusher clasp rotator 292 is illustrated in FIGS. 30 through 35. Alsodisposed between the clasp rotator 292 and the graft push lumen 642 is arotator body 294, which is directly adjacent the graft push lumen 642. Aspecific embodiment of the rotator body 294 is illustrated in FIGS. 40through 43. Disposed between the rotator body 294 and the sheath lumen654 is a pusher clasp body 296, which is fixedly connected to therotator body 294 and to the locking ring 676. A specific embodiment ofthe pusher clasp body 296 is illustrated in FIGS. 44 through 46. Apusher clasp spring 298 operatively connects the pusher clasp rotator292 to the rotator body 294 (and, thereby, the pusher clasp body 296).

An exploded view of these components is presented in FIG. 48, where anO-ring 293 is disposed between the rotator body 294 and the pusher claspbody 296. As shown in the plan view of FIG. 47, a crimp ring 295connects the sheath lumen 654 to the distal projection 297 of the pusherclasp body 296. A hollow handle body 674, on which the proximal handle678 and the locking ring 676 are slidably mounted, holds the pusherclasp rotator 292, the rotator body 294, the pusher clasp body 296, andthe pusher clasp spring 298 therein. This entire assembly isrotationally mounted to the distal handle 672 for rotating the stentgraft 1 into position (see FIGS. 23 and 24 and the explanations thereofbelow). A specific embodiment of the handle body 674 is illustrated inFIG. 49.

A setscrew 679 extends from the proximal handle 678 to contact alongitudinally helixed groove in the pusher clasp rotator 292 (shown inFIGS. 36 and 38). Thus, when moving the proximal handle 678 proximallyor distally, the pusher clasp rotator 292 rotates clockwise orcounter-clockwise.

An alternative embodiment of the locking ring 676 is shown in FIG. 50 etseq., which is the preferred embodiment because, instead of applying alongitudinal movement to rotate the pusher clasp spring 298 through thecam/follower feature of the proximal handle 678 and pusher clasp rotator292, a rotating locking knob 582 is located at the proximal end of thehandle body 674. The knob 582 has three positions that are clearly shownin FIG. 51: a neutral position N, an advancement position A, and adeployment position D. The functions of these positions N, A, Dcorrespond to the positions N, A, D of the locking ring 676 and theproximal handle 678 as set forth above.

In the alternative embodiment, a setscrew 584 is threaded into the claspsleeve 614 through a slot 675 in the handle body 674 and through a slot583 in the knob 582 to engage the locking knob 582. Because of thex-axis orientation of the slot 583 in the knob 582 and the y-axisorientation of the slot 675 in the handle body 674, when the knob 582 isslid over the end of the handle body 674 and the setscrew 584 is screwedinto the clasp sleeve 614, the knob 582 is connected fixedly to thehandle body 674. When the locking knob 582 is, thereafter, rotatedbetween the neutral N, advancement A, and deployment D positions, theclasp sleeve 614 rotates to actuate the spring lock (see FIGS. 48 and52).

A setscrew 586, shown in FIG. 53, engages a groove 605 in the proximalclasp assembly 604 to connect the proximal clasp assembly 604 to theclasp sleeve 614 but allows the clasp sleeve 614 to rotate around theclasp body 602. The clasp sleeve 614 is shown in FIGS. 50 and 53 and, inparticular, in FIGS. 59 to 62. The proximal clasp assembly 604 of FIG.53 is more clearly shown in the exploded view of FIG. 52. The proximalclasp assembly 604 is made of the components including a proximal spring606, a locking washer 608, a fastener 603 (in particular, a screwfitting into internal threads of the proximal clasp body 602), and aproximal clasp body 602. The proximal clasp body 602 is shown, inparticular, in FIGS. 54 through 58. The proximal clasp assembly 604 isconnected fixedly to the handle body 674, preferably, with a screw 585shown in FIG. 50 and hidden from view in FIG. 51 under knob 582.

The handle body 674 has a position pin 592 for engaging in positionopenings at the distal end of the locking knob 582. The position pin 592can be a setscrew that only engages the handle body 674. When thelocking knob 582 is pulled slightly proximally, therefore, the knob canbe rotated clockwise or counter-clockwise to place the pin 592 into theposition openings corresponding to the advancement A, neutral N, anddeployment D positions.

As shown in FIG. 18, to begin deployment of the stent graft 1, theuser/physician grasps both the distal handle 672 and the proximal handle678 and slides the proximal handle 678 towards the distal handle 672 inthe direction indicated by arrow A. This movement, as shown in FIGS. 19to 21, causes the flexible inner sheath 652, holding the compressedstent graft 1 therein, to emerge progressively from inside the outercatheter 660. Such a process allows the stent graft 1, while constrainedby the inner sheath 652, to expand to a larger diameter as shown in FIG.12, this diameter being substantially larger than the inner diameter ofthe outer catheter 660 but smaller than the inner diameter of the vesselin which it is to be inserted. Preferably, the outer catheter 660 ismade of a polymer (co-extrusions or teflons) and the inner sheath 652 ismade of a material, such as a fabric/woven polymer or other similarmaterial. Therefore, the inner sheath 652 is substantially more flexiblethan the outer catheter 660.

It is noted, at this point, that the inner sheath 652 contains a taper653 at its proximal end, distal to the sheath's 652 connection to thesheath lumen 654 (at which the inner sheath 652 has a similar diameterto the distal sleeve 644 working in conjunction with the distal sleeve644 to capture the distal end 14 of the stent graft 1. The taper 653provides a transition that substantially prevents any kinking of theouter catheter 660 when the stent graft 1 is loaded into the deliveryassembly 600 (as in the position illustrated in FIGS. 10 and 11) and,also, when the outer catheter 660 is navigating through the femoral andiliac vessels. One specific embodiment of the sheath lumen 654 has alength between approximately 35 and 37 inches, in particular, 36 inches,an outer diameter of between approximately 0.20 and 0.25 inches, inparticular 0.238 inches, and an inner diameter between approximately0.18 and approximately 0.22 inches, in particular, 0.206 inches.

When the proximal handle 678 is moved towards its distal position, shownby the dashed lines in FIG. 11, the nose cone assembly 630 and thesheath assembly 650 move towards a second position where the sheathassembly 650 is entirely out of the outer catheter 660 as shown in FIGS.20 and 21. As can be seen most particularly in FIGS. 20 and 21, as thenose cone assembly 630 and the sheath assembly 650 are emerging out ofthe outer catheter 660, they are traversing the curved portion 710 ofthe descending aorta. The tracking is accomplished visually by viewingradiopaque markers on various portions of the delivery system and/or thestent graft 1 with fluoroscopic measures. Such markers will be describedin further detail below. The delivery system can be made visible, forexample, by the nose cone 630 being radiopaque or containing radiopaquematerials.

It is noted that if the harder outer catheter 660 was to have been movedthrough the curved portion 710 of the aorta 700, there is a great riskof puncturing the aorta 700, and, particularly, a diseased portion 744of the proximal descending aorta 710 because the outer catheter 660 isnot as flexible as the inner sheath 652. But, because the inner sheath652 is so flexible, the nose cone assembly 630 and the sheath assembly650 can be extended easily into the curved portion 710 of the aorta 700with much less force on the handle than previously needed with prior artsystems while, at the same time, imparting harmless forces to theintraluminal surface of the curved aorta 710 due to the flexibility ofthe inner sheath 652.

At the second position shown in FIG. 21, the user/physician, usingfluoroscopic tracking of radiopaque markers (e.g., marker 631) on anyportion of the nose cone or on the stent graft 1 and/or sheathassemblies 630, 650, for example, makes sure that the proximal end 112of the stent graft 1 is in the correct longitudinal position proximal tothe diseased portion 744 of the aorta 700. Because the entire insertedassembly 630, 650 in the aorta 700 is still rotationally connected tothe portion of the handle assembly 670 except distal handle 672 (distalhandle 672 is connected with the outer sheath 660 and rotatesindependently of the remainder of the handle assembly 670), thephysician can rotate the entire inserted assembly 630, 650 clockwise orcounterclockwise (indicated in FIG. 21 by arrow B) merely by rotatingthe proximal handle 678 in the desired direction. Such a feature isextremely advantageous because the non-rotation of the outer catheter660 while the inner sheath 652 is rotating eliminates stress on thefemoral and iliac arteries when the rotation of the inner sheath 652 isneeded and performed.

Accordingly, the stent graft 1 can be pre-aligned to place the stentgraft 1 in the correct circumferential position—defined by placing thelongitudinal support member 40 substantially at the superiorlongitudinal surface line of the curved aorta (with respect toanatomical position). FIG. 23 illustrates the longitudinal supportmember 40 not in the correct superior position and FIG. 24 illustratesthe longitudinal support member 40 in the correct superior position. Thesuperior surface position is, preferably, the longest superiorlongitudinal line along the circumference of the curved portion of theaorta as shown in FIGS. 23 and 24. As set forth above, when thelongitudinal support member 40 extends along the superior longitudinalline of the curved aorta, the longitudinal support member 40substantially eliminates any possibility of forming a kink in theinferior radial curve of the stent graft 1 during use and also allowstransmission of longitudinal forces exerted along the inside lumen ofthe stent graft 1 to the entire longitudinal extent of the stent graft1, thereby allowing the entire outer surface of the stent graft 1 toresist longitudinal migration.

In prior art stent grafts and stent graft delivery systems, the stentgraft is, typically, provided with symmetrically-shaped radiopaquemarkers along one longitudinal line and at least one othersymmetrically-shaped radiopaque marker disposed along anotherlongitudinal line on the opposite side (180 degrees) of the stent graft.Thus, using two-dimensional fluoroscopic techniques, the only way todetermine if the stent graft is in the correct rotational position is byhaving the user/physician rotate the stent graft in both directionsuntil it is determined that the first longitudinal line is superior andthe other longitudinal line is anterior. This required more work by thephysician and is, therefore, undesirable.

According to a preferred embodiment of the invention illustrated inFIGS. 27 and 28, unique radiopaque markers 232, 234 are positioned onthe stent graft 1 to assist the user/physician in correctly positioningthe longitudinal support member 40 in the correct aortic superiorsurface position with only one directional rotation that is also theminimal rotation needed to place the stent graft 1 in the rotationallycorrect position.

Specifically, the stent graft 1 is provided with a pair of symmetricallyshaped but diametrically opposed markers 232, 234 indicating to theuser/physician which direction the stent graft 1 needs to be rotated toalign the longitudinal support member 40 to the superior longitudinalline of the curved aorta (with respect to anatomical position).Preferably, the markers 232, 234 are placed at the proximate end 12 ofthe graft sleeve 10 on opposite sides (180 degrees) of the graft sleeve10.

The angular position of the markers 232, 234 on the graft sleeve 10 isdetermined by the position of the longitudinal support member 40. In apreferred embodiment, the support member 40 is between the two markers232, 234. To explain such a position, if the marker 232 is at a 0 degreeposition on the graft sleeve 10 and the marker 234 is at a 180 degreeposition, then the centerline 45 of the support member 40 is at a 90degree position. However, an alternative position of the markers canplace the marker 234 90 degrees away from the first degree 41 (see FIG.1). Such a positioning is dependent somewhat upon the way in which theimplantation is to be viewed by the user/physician and can be variedbased on other factors. Thus, the position can be rotated in anybeneficial way.

Preferred ancillary equipment in endovascular placement of the stentgraft 1 is a fluoroscope with a high-resolution image intensifiermounted on a freely angled C-arm. The C-arm can be portable, ceiling, orpedestal mounted. It is important that the C-arm have a complete rangeof motion to achieve AP to lateral projections without moving thepatient or contaminating the sterile field. Capabilities of the C-armshould include: Digital Subtraction Angiography, High-resolutionAngiography, and Roadmapping.

For introduction of the delivery system into the groin access arteries,the patient is, first, placed in a sterile field in a supine position.To determine the exact target area for placement of the stent graft 1,the C-arm is rotated to project the patient image into a left anterioroblique projection, which opens the radial curve of the thoracic aorticarch for optimal visualization without superimposition of structures.The degree of patient rotation will vary, but is usually 40 to 50degrees. At this point, the C-arm is placed over the patient with thecentral ray of the fluoroscopic beam exactly perpendicular to the targetarea. Such placement allows for the markers 232, 234 to be positionedfor correct placement of the stent graft 1. Failure to have the centralray of the fluoroscopic beam perpendicular to the target area can resultin parallax, leading to visual distortion to the patient anatomy due tothe divergence of the fluoroscopic x-ray beam, with a resultantmisplacement of the stent graft 1. An angiogram is performed and theproposed stent graft landing zones are marked on the visual monitor.Once marked, neither the patient, the patient table, nor thefluoroscopic C-arm can be moved, otherwise, the reference markers becomeinvalid. The stent graft 1 is, then, placed at the marked landing zones.

In a preferred embodiment, the markers 232, 234 are hemispherical, inother words, they have the approximate shape of a “D”. This shape ischosen because it provides special, easy-to-read indicators thatinstantly direct the user/physician to the correct placement positionfor the longitudinal support member 40. FIG. 27, for example,illustrates a plan view of the markers 232, 234 when they are placed inthe upper-most superior longitudinal line of the curved aorta. Thecorrect position is indicated clearly because the two hemispheres havethe flat diameters aligned on top of or immediately adjacent to oneanother such that a substantially complete circle is formed by the twohemispherically rounded portions of the markers 232, 234. This positionis also indicated in the perspective view of FIG. 28.

Each of FIGS. 27 and 28 have been provided with examples where themarkers 232, 234 are not aligned and, therefore, the stent graft 1 isnot in the correct insertion position. For example, in FIG. 27, twomarkers 232′, 234′ indicate a misaligned counter-clockwise-rotated stentgraft 1 when viewed from the plane 236 at the right end of the stentgraft 1 of FIG. 23 looking toward the left end thereof and down the axis11. Thus, to align the markers 232′, 234′ in the most efficient waypossible (the shortest rotation), the user/physician sees that thedistance between the two flat diameters is closer than the distancebetween the highest points of the hemispherical curves. Therefore, it isknown that the two flat diameters must be joined together by rotatingthe stent graft 1 clockwise.

FIG. 28 has also been provided with two markers 232″, 234″ indicating amisaligned clockwise-rotated stent graft 1 when viewed from the plane236 at the right end of the stent graft 1 of FIG. 27 looking toward theleft end thereof and down the axis 11. Thus, to align the markers 232″,234″ in the most efficient way possible (the shortest rotation), theuser/physician sees that the distance between the highest points of thehemispherical curves is smaller than the distance between the two flatdiameters. Therefore, it is known that the two flat diameters must bejoined together by rotating the stent graft 1 in the direction that thehighest points of the hemispherical curves point; in other words, thestent graft 1 must be rotated counter-clockwise.

A significant advantage provided by the diametrically opposed symmetricmarkers 232, 234 is that they can be used for migration diagnosisthroughout the remaining life of a patient after the stent graft 1 hasbeen placed inside the patient's body. If fluoroscopic or radiographictechniques are used any time after the stent graft 1 is inserted in thepatient's body, and if the stent graft 1 is viewed from the same angleas it was viewed when placed therein, then the markers' 232, 234relative positions observed should give the examining individual a veryclear and instantaneous determination as to whether or not the stentgraft 1 has migrated in a rotational manner.

The hemispherical shape of the markers 232, 234 are only provided as anexample shape. The markers 232, 234 can be any shape that allows auser/physician to distinguish alignment and direction of rotation foralignment. For example, the markers 232, 234 can be triangular, inparticular, an isosceles triangle having the single side be visiblylonger or shorter than the two equal sides.

When the stent graft 1 is in place both longitudinally andcircumferentially (FIG. 21), the stent graft 1 is ready to be removedfrom the inner sheath 652 and implanted in the vessel 700. Becauserelative movement of the stent graft 1 with respect to the vessel is nolonger desired, the inner sheath 652 needs to be retracted while thestent graft 1 remains in place, i.e., no longitudinal or circumferentialmovement. Such immovability of the stent graft 1 is insured by, first,the apex capture device 634 of the nose cone assembly 630 holding thefront of the stent graft 1 by its bare stent 30 (see FIGS. 13, 22, and23) and, second, by unlocking the locking ring 676/placing the lockingring/knob in the D position—which allows the sheath lumen 654 to moveindependently from the guidewire lumen 620, apex release lumen 640, andgraft push lumen 642. The apex capture device 634, as shown in FIGS. 13,14, 30 and 311 (and as will be described in more detail below), isholding each individual distal apex 32 of the bare stent 30 in a securemanner—both rotationally and longitudinally.

The nose cone assembly 630, along with the apex capture device 634, issecurely attached to the guidewire lumen 620 (and the apex release lumen640 at least until apex release occurs). The inner sheath 652 issecurely attached to a sheath lumen 654, which is coaxially disposedaround the guidewire lumen 620 and fixedly attached to the proximalhandle 678. The stent graft 1 is also supported at its distal end by thegraft push lumen 642 and the distal sleeve 644 or the taper 653 of theinner sheath 652. (The entire coaxial relationship of the various lumen610, 620, 640, 642, 654, and 660 is illustrated for exemplary purposesonly in FIG. 25, and a portion of which can also be seen in the explodedview of the handle assembly in FIG. 50) Therefore, when the proximalhandle 678 is moved proximally with the locking ring 676 in thedeployment position D, the sheath lumen 654 moves proximally as shown inFIGS. 13, 22, and 23, taking the sheath 652 proximally along with itwhile the guidewire lumen 620, the apex release lumen 640, the graftpush lumen 642, and the distal sleeve 644 remain substantiallymotionless and, therefore, the stent graft 1 remains both rotationallyand longitudinally steady.

The stent graft 1 is, now, ready to be finally affixed to the aorta 700.To perform the implantation, the bare stent 30 must be released from theapex capture device 634. As will be described in more detail below, theapex capture device 634 shown in FIGS. 13, 14, and 29 to 32, holds theproximal apices 32 of the bare stent 30 between the distal apex head 636and the proximal apex body 638. The distal apex head 636 is fixedlyconnected to the guidewire lumen 620. The proximal apex body 638,however, is fixedly connected to the apex release lumen 640, which iscoaxial with both the guidewire lumen 620 and the sheath lumen 654 anddisposed therebetween, as illustrated diagrammatically in FIG. 25. (Aswill be described in more detail below, the graft push lumen 642 is alsofixedly connected to the apex release lumen 640.) Therefore, relativemovement of the apex release lumen 640 and the guidewire lumen 620separates the distal apex head 636 and a proximal apex body 638 from oneanother.

To cause such relative movement, the apex release assembly 690 has, in apreferred embodiment, three parts, a distal release part 692, a proximalrelease part 694, and an intermediate part 696 (which is shown in theform of a clip in FIGS. 16 and 26). To insure that the distal apex head636 and the proximal apex body 638 always remain fixed with respect toone another until the bare stent 30 is ready to be released, theproximal release part 694 is formed with a distal surface 695, thedistal release part 692 is formed with a proximal surface 693, and theintermediate part 696 has proximal and distal surfaces corresponding tothe surfaces 695, 693 such that, when the intermediate part 696 isinserted removably between the distal surface 695 and the proximalsurface 693, the intermediate part 696 fastens the distal release part692 and the proximal release part 694 with respect to one another in aform-locking connection. A form-locking connection is one that connectstwo elements together due to the shape of the elements themselves, asopposed to a force-locking connection, which locks the elements togetherby force external to the elements. Specifically, as shown in FIG. 26,the clip 696 surrounds a distal plunger 699 of the proximal release part694 that is inserted slidably within a hollow 698 of the distal releasepart 692. The plunger 699 of the proximal release part 694 can slidewithin the hollow 698, but a stop 697 inside the hollow 698 prevents thedistal plunger 699 from withdrawing from the hollow 698 more than thelongitudinal span of the clip 696.

To allow relative movement between the distal apex head 636 and theproximal apex body 638, the intermediate part 696 is removed easily withone hand and, as shown from the position in FIG. 16 to the position inFIG. 17, the distal release part 692 and the proximal release part 694are moved axially towards one another (preferably, the former is movedtowards the latter). Such movement separates the distal apex head 636and the proximal apex body 638 as shown in FIG. 14. Accordingly, thedistal apices 32 of the bare stent 30 are free to expand to theirnatural position in which the bare stent 30 is released against thevessel 700.

Of course, the apex release assembly 690 can be formed with any kind ofconnector that moves the apex release lumen 640 and the guidewire lumen620 relative to one another. In a preferred alternative embodiment, forexample, the intermediate part 696 can be a selectable lever that isfixedly connected to either one of the distal release part 692 or theproximal release part 694 and has a length equal to the width of theclip 696 shown in FIG. 26. Thus, when engaged by pivoting the leverbetween the distal release part 692 and the proximal release part 694,for example, the parts 692, 694 cannot move with respect to one anotherand, when disengaged by pivoting the lever out from between the parts692, 694, the distal release part 692 and the proximal release part 694are free to move towards one another.

The apex clasp device is unique to the present invention in that itincorporates features that allow the longitudinal forces subjected onthe stent graft 1 to be fully supported, through the bare stent 30, byboth the guidewire lumen 620 and apex release lumen 640. Support occursby providing the distal apex head 636 with a distal surface 639supporting the proximal apices 32 of the bare stent 30, which isparticularly shown in the enlarged perspective view of the distal apexhead 636 provided in FIG. 29. The distal surface 639, in turn, rests onthe proximal apex body 638 when in the closed position, as more clearlyshown in FIGS. 30 and 31. Thus, the longitudinal forces are fullytransmitted to both the guidewire lumen 620 and apex release lumen 640,making the assembly much stronger.

Having the distal surface 639 be the load-bearing surface of theproximal apices 32 ensures expansion of the each one of the distalapices 32 from the apex release assembly 690. The proximal surface 641of the distal apex head 636 meets with the interior surfaces of theproximal apex body 638 to help carry the apex load because the apices ofthe bare stent 30 are captured therebetween when the apex capture device634 is closed. Such capture can be clearly seen in the cut-away view ofthe proximal apex body 638 in FIG. 31. For release of the apices 32 ofthe bare stent 30, the proximal apex body 638 moves to the left (withrespect to FIG. 32). Because of friction occurring between the apices 32and the “teeth” of the proximal apex body 638 when the apices 32 arecaptured, the apices 32 will also try to move to the left along with theproximal apex body 638 and, if allowed to do so, possibly would neverclear the “teeth” to allow each apex 32 to expand. However, as theproximal apex body 638 disengages (moves in the direction of arrow C inFIG. 31), direct contact with the distal surface 639 entirely preventsthe apices 32 from sliding in the direction of arrow C along with theproximal apex body 638 to ensure automatic release of every capturedapex 32 of the bare stent 30. Because the proximal apex body 638continues to move to the left, eventually the “teeth” will clear theirrespective capture of the apices 32 and the bare stent 30 will,therefore, expand entirely. The release position of the distal apex head636 and the proximal apex body 638 is shown in FIG. 32, and correspondsto the position of the apex release assembly 690 in FIG. 17. As can beseen, tapers on the distal outer surfaces of the proximal apex body 638further assist in the prevention of catching the proximal apices 32 ofthe bare stent 30 on any part of the apex capture device 634.

Simply put, the apex capture device 634 provides support for load placedon the stent graft 1 during advancement A of the inner sheath 652 andduring withdrawal of the inner sheath 652 (i.e., during deployment D).Such a configuration benefits the apposition of the bare stent 30 byreleasing the bare stent 30 after the entire graft sleeve 10 has beendeployed, thus reducing the potential for vessel perforation at thepoint of initial deployment.

When the stent graft 1 is entirely free from the inner sheath 652 asshown in FIG. 23, the proximal handle 678 is, then, substantially at ornear the third position (deployment position) shown in FIG. 10.

The stent graft 1 is, now, securely placed within the vessel and theentire portion 630, 650, 660 of the assembly 600 may be removed from thepatient.

While the preferred embodiments of the invention have been illustratedand described, it will be clear that the invention is not so limited.Numerous modifications, changes, variations, substitutions, andequivalents will occur to those skilled in the art without departingfrom the spirit and scope of the present invention as defined by theappended claims.

1. A method for manufacturing a stent, comprising the steps of: a)winding stent wire around an outer surface of a longitudinal axis of amandrel having a polygonal cross-sectional shape into a desired finalshape that is polygonal in an elevation orthogonal to the longitudinalaxis; and b) forming a stent by setting the wound stent wire in thedesired polygonal final shape, whereby the outside diameter of the stentwill be in co-columnar apposition with a blood vessel in which it isimplanted.
 2. The method according to claim 1, wherein the mandrelfurther includes flat sections and rounded edge portions between theflat sections.
 3. The method according to claim 2, further includingcarrying out the stent forming step by setting the stent wire to haverounded edges corresponding to the rounded edge portions of the mandreland with flat sides corresponding to the flat sections of the mandrel.4. The method according to claim 1, further including the steps of: c)placing pins on the outer surface of the mandrel longitudinally offsetfrom one another and corresponding to desired Z-stent apex locations;and d) forming Z-stent apices by winding the stent wire around the pins.5. The method according to claim 4, wherein the pins are placed on themandrel to protrude perpendicularly from the outside surface of themandrel.
 6. The method according to claim 2, further including the stepsof: c) placing pins on at least some of the rounded edge portions of themandrel longitudinally offset from one another and corresponding todesired Z-stent apex locations; and d) forming Z-stent apices by windingthe stent wire around the pins.
 7. The method according to claim 6,wherein the pins are placed at each of the rounded edge portions of themandrel and the stent is set with substantially linear struts lying flatagainst the flat sections of the mandrel.
 8. The method according toclaim 1, wherein the mandrel has a dodecahedron shape and a Z-stenthaving six proximal and six distal apices is formed.
 9. The methodaccording to claim 1, further including the step of fastening two endsof the stent wire to one another to complete the stent.
 10. The methodaccording to claim 1, wherein the stent wire is initially wound aroundthe outer surface of the longitudinal axis of the mandrel as acold-drawn shape-memory wire and the stent is formed by heat-treatment.11. The method according to claim 10, wherein the heat-treatmentincludes exposing the shape-memory wire to a heat-setting temperaturefor a period of time with subsequent quenching as required to shape setthe shape-memory wire to the then-existing shape of the wire on themandrel and obtain superelastic mechanical characteristics of theshape-memory wire.
 12. The method according to claim 1, wherein thestent is formed by exposing the stent wire to a process that shapes thewire to the then-existing shape of the wire on the mandrel selected fromat least one of the group consisting of a mechanical process, a thermalprocess, and a chemical process.
 13. A method for manufacturing a stent,comprising the steps of: a) winding a stent wire around an outer surfaceof a longitudinal axis of a mandrel having a multiple-sided outersurface into a desired final shape substantially corresponding to ashape of the outer surface; and b) forming a stent by setting the woundstent wire into the desired final shape, whereby the outside diameter ofthe stent will be in co-columnar apposition with a blood vessel in whichit is implanted.
 14. The method according to claim 13, wherein themandrel includes flat sections and rounded edge portions between theflat sections and the stent is formed by setting the stent wire to haverounded edges corresponding to the rounded edge portions of the mandreland with flat sides corresponding to the flat sections of the mandrel.15. The method according to claim 14, further including the steps of: c)placing pins on the outer surface of the mandrel protrudingperpendicularly therefrom and being longitudinally offset from oneanother to correspond with desired Z-stent apex locations; and d)forming Z-stent apices of the stent by winding the stent wire around thepins.
 16. The method according to claim 15, wherein the pins are placedon each of the rounded edge portions of the mandrel.
 17. The methodaccording to claim 13, further including the step of fastening two endsof the stent wire to one another to complete the stent.
 18. The methodaccording to claim 13, wherein the stent wire is initially wound aroundthe outer surface of the longitudinal axis of the mandrel as acold-drawn shape-memory wire and the stent is formed by heat-treatment.19. The method according to claim 18, wherein the heat-treatmentincludes exposing the shape-memory wire to a heat-setting temperaturefor a period of time with subsequent quenching as required to shape setthe shape-memory wire to the then-existing shape of the wire on themandrel and obtain superelastic mechanical characteristics of theshape-memory wire.
 20. The method according to claim 13, wherein thestent is formed by exposing the stent wire to a process that shapes thewire to the then-existing shape of the wire on the mandrel selected fromat least one of the group consisting of a mechanical process, a thermalprocess, and a chemical process.